With a polymer electrolyte fuel cell using hydrogen as fuel, excessive hydrogen expelled from a fuel cell stack is supplied to an inlet of the fuel cell stack whereby hydrogen is supplied to the fuel cell stack at a larger supply rate than that of hydrogen to be consumed in the fuel cell stack for enabling stable electric power generation.
Japanese Patent Application Laid-Open Publication No. 2001-266922 discloses a fuel cell system that includes an ejector whose secondary flow guide pipe is introduced with exhaust fuel, expelled from a fuel exhaust port of a fuel cell stack, through a check valve, with exhaust fuel expelled from the fuel cell being recirculated through the ejector. By recirculating excessive hydrogen expelled from the fuel cell stack to an inlet of the fuel cell stack through the ejector, it attempts to achieve stable electric power generation while supplying hydrogen to the fuel cell stack at a larger supply rate than that of hydrogen to be consumed in the fuel cell stack without deserting the excessive hydrogen.